Compression: Terminate workers after use

While the browser engine can clean up workers automatically, it's a good
idea to terminate them as soon as we don't need those anymore. It's
generally suggested to reuse a single worker for repetitive operations,
but implementing such a system is much harder. In addition, spawning a
new worker for each operation allows (de)compressing multiple blobs in
parallel :)

src/js/core/compression.ts

@@ -23,6 +23,7 @@ export class DefaultCompression implements Compression {
             resolve(response.result);
         });
 
+        this.scheduleWorkerTermination(worker);
         worker.postMessage(data);
         return promise;
     }
@@ -43,7 +44,13 @@ export class DefaultCompression implements Compression {
             resolve(response.result);
         });
 
+        this.scheduleWorkerTermination(worker);
         worker.postMessage(data, [data.buffer]);
         return promise;
     }
+
+    private scheduleWorkerTermination(worker: Worker): void {
+        worker.addEventListener("message", () => worker.terminate(), { once: true });
+        worker.addEventListener("error", () => worker.terminate(), { once: true });
+    }
 }